A two-stage aerosol impactor with embedded MEMS resonant mass balances for particulate size segregation and mass concentration monitoring

This work reports on integration of MEMS resonant mass balances within a two-stage aerosol impactor capable of sampling and size separation of micro to nanoscale airborne particles. Two identical thin-film piezoelectric on substrate (TPoS) resonators acting as high resolution mass balances provide real-time information on mass concentration of size-segregated airborne particles adsorbed in each aerosol impactor stage. Tests performed on air samples from different environments with different particle mass concentrations ranging from 0.014-0.2μg/m³ (particles larger than 60nm) show a clear correlation between the resonator response and the expected particle concentrations. SEM images of the deposited particles clearly show a size difference between particles collected in the two stages with the cutoff sizes close to the values the impactor was originally designed for (230nm and 60nm for the first and second stages, respectively).